JP2020137409A - Device for protecting at least two electrical cables against electric arc - Google Patents

Abstract

To provide a protection device and a power supply system that have a better resistance capacity against electric arcs, while ensuring sufficient protection of the power supply system as well as a simple operation of the power supply system.SOLUTION: A device (20) for protecting at least two electrical cables against an electric arc, each electrical cable comprising at least one electrical terminal, comprises: a body (30) comprising a front face (45) in which orifices (47) intended to receive corresponding electrical terminals of the respective electrical cables are formed; first and second faces (40, 42) arranged on either side of the front face (45); at least one magnetic element (32) together generating a magnetic field, each magnetic element (32) being fixed to the first face (40) or the second face; and a first guide element (34a) and a second guide element (34b) for the magnetic field (B) fixed to the first face (40).SELECTED DRAWING: Figure 2

Description

The present invention relates to a protective device against arcs of at least two electric cables. The present invention also relates to a power feeding system.

More specifically, the present invention relates to the field of power supply for rail vehicles, more precisely the protection of electrical equipment.

Already, in the current state of the art, rail vehicle power supply systems including electrical connections (Connextion e'lectrique) that connect a power supply unit to an electric motor, such as a traction motor, are well known. For example, the power supply unit is fixed on the roof of the railroad vehicle, and the electric motor is arranged in the carriage of the railroad vehicle.

Electrical connections include power cables that include electrical terminals and switches.

When generating the voltage in the power supply cable, an arc may occur between the cables. Multiple arc sources are well known.

For example, the electric motor can be a motor that includes a permanent magnet. Permanent magnets generate a magnetic field every moment. When the stator of the electric motor is rotating, a voltage is induced in the electric terminals of the motor. This voltage can induce arcs within the feeding system, especially between cables.

Such arcs are extremely destructive to power supply systems, especially the power supply cables of these systems.

Protective devices are known for the purpose of protecting the feeding system against the propagation of such arcs in the feeding system. Protective material is typically interpose's between the cables and between the cables and the environment.

However, if the protective materials are exposed's for an extended period of time, they will deteriorate and no longer protect the power supply system. As a result, protective materials must be replaced frequently to avoid arc expansion.

Therefore, such protective devices are not completely satisfactory.

Therefore, it is an object of the present invention to provide a protective device and power supply system having better resistance to arc (capacite'de re'sistance) while ensuring sufficient protection of the power supply system and simple operation of the power supply system. To make a suggestion.

Therefore, the present invention is intended to be a protective device for arcing at least two electric cables, each of which has at least one electrical terminal. The protective device is
-A body having a front surface provided with an orifice intended to accommodate the electrical terminals of each electrical cable, and first and second surfaces located on either side of the front surface.
-At least one magnetic element, each magnetic element fixed on a first or second surface, together with at least one magnetic element that produces a magnetic field.
-A first guiding element of a magnetic field fixed to a first surface and a second guiding element of a magnetic field fixed to a second surface, configured to allow the magnetic field to pass between each other. , Preferably, the first and second inductive elements that extend beyond the body so that they are intercale'es when the electrical terminals are housed in the orifice. Have.

The protective device makes it possible to obtain better protection against the arc of the cable by exposing the arc to a magnetic field and thus correcting the direction of propagation of the arc. In particular, the guiding element allows the magnetic field to pass so as to deflect the arc. As a result, the cable is less exposed to the arc.

When the arc is deflected towards the body of the protective device, the fins can fragment the arc extending between the two cables into multiple fragmentation arcs. For example, these split arcs disappear between the fins. The fins thus contribute to the resistance of the protective device.

The protective device according to the invention can have one or more of the following features, either individually or according to any combination technically possible.
-The body has a plurality of magnetic elements having at least one first magnetic element fixed on the first surface and at least one second magnetic element fixed on the second surface. The first magnetic element and the second magnetic element both generate a magnetic field.
-Each orifice extends along the orifice axis, and the body is further on its anterior surface, fins configured to split the arc, along a direction parallel to each orifice axis. It has extending fins.
-The body has at least one orifice pair, and the body has a group of at least two fins disposed between the orifices of each orifice pair.
-Each fin is at least partially covered with a reve ^ tement with me'tal inoxydable.
-The magnetic elements are oriented to generate a magnetic field along the direction perpendicular to the first and second planes.
-Each orifice extends along the orifice axis, which extends parallel to the first and second planes.
-The protective device has at least three orifices aligned in a direction parallel to the first and second planes.
-The body has a first cavity on the first surface and a second cavity on the second surface, the first magnetic element is housed in the first cavity and the second magnetic element. Is housed in a second cavity.

Similarly, the present invention also provides a power supply system for rolling stock, comprising at least one electric traction motor and an electrical connection configured to power the electric motor. The electrical connection has at least one protective device as described above.

Optionally, the electric motor is a permanent magnet motor.

It is the schematic of the power supply system which concerns on an example of embodiment of this invention. It is a schematic perspective view of the protection device of the power supply system of FIG. It is the schematic perspective view of the protection device of FIG. 2 which shows the deflection of an arc. It is the schematic perspective view of the protection device of FIG. 2 which shows the deflection of an arc. It is the schematic sectional drawing of a part of the protection device of FIG.

The present invention is better understood by reading the following description provided as an example and with reference to the accompanying drawings.

FIG. 1 represents a power supply system 1 for a railroad vehicle. The power supply system 1 includes a power supply unit 10, two electric motors 12, and two electric connections 14 that connect each power supply unit 10 to each motor 12.

In one variant not shown, the power supply system includes only one electrical connection and only one electric motor.

Further, in one variant (not shown), the power supply system includes at least three motors and three electrical connections that connect each power supply unit to each electric motor.

The power supply unit 10 is arranged, for example, on the roof of a railway vehicle (not shown). For example, the power supply unit 10 is connected to a catenary (not shown) on the one hand and to an electrical connection 14 on the other.

The power supply unit 10 is configured to transfer power from the catenary to the electrical connection 14.

Each electric motor 12 is intended to be powered by the corresponding electrical wiring. Each electric motor 12 is, for example, an AC motor. More specifically, in the illustrated embodiment, each electric motor 12 is a three-phase motor. This motor is configured to be fed by the current flowing through the three electric cables 16.

Each electric motor 12 is, for example, a traction motor for a railway vehicle.

Each electric motor 12 includes, for example, a permanent magnet. When the train moves without the power supply of the motor 12, the permanent magnets generate a voltage in the electrical connection 14. Such a voltage can induce an arc.

Each electrical connection 14 includes a connector 18, a switch 22, and a protective device 20 connected in series by an electrical cable 16 in the embodiment of FIG.

Hereinafter, one of the electrical connections 14 will be described in more detail, but the other electrical connections 14 are also the same.

In the embodiment of FIG. 1, the electrical connection 14 includes three cables 16 that connect the power supply unit 10 and the corresponding motor 12. The three cables 16 are configured to power the corresponding electric motor 12.

Each cable 16 includes a conductive core wire (ame conductrice) 24 and a cable exterior (gai ^ ne de cable) 26, and an electrical terminal 28 (one terminal of each of these cables is shown in FIGS. 3 and 4). Has an end that forms (especially visible in).

The connector 18 is, for example, a male contact. The connector 18 is for connecting the power supply unit 10 to the electric cable 16.

The switch 22 is for interrupting the electrical coupling between the power supply unit 10 and the corresponding motor 12. Such a switch 22 is known to those skilled in the art. It should be pointed out that an arc can be formed within the switch 22 or between the electrical terminals 28.

The protective device 20 is specifically for stopping the propagation of the arc along the cable 16.

The protective device 20, which is represented in detail by FIG. 2, includes a main body 30, a magnetic element 32, and first and second guiding elements 34a, 34b.

According to one embodiment (not shown), the protective device 20 includes only one magnetic element 32.

The main body 30 includes an insulating material that separates the electric cables 16 from each other.

The body 30 has the overall shape of a parallelepiped including, for example, a first surface called the upper surface 40 and a second surface opposite the upper surface 40, for example called the lower surface 42. The upper surface 40 and the lower surface 42 are arranged on both sides of the front surface 45.

The upper surface 40 and the lower surface 42 are particularly parallel to each other. The body 30 further includes lateral sides 43, 44 and a front surface (eg, what is visible in FIG. 2) 45 and a rear surface 46. The side surfaces 43, 44 and the front surface 45 and the rear surface 46 are perpendicular to the upper surface 40 and the lower surface 42. The lateral surfaces 43, 44 are further perpendicular to the front surface 45 and the rear surface 46.

The names "upper", "lower", "side", "forward" and "rear" are arbitrarily based on FIG. 2 and do not presume any orientation within the power supply system.

In the embodiment of FIG. 1, the front surface 45 is oriented toward the power feeding unit 10, and the rear surface is oriented toward the electric motor 12.

In the illustrated embodiment, the body 30 has orifices 47 configured to accommodate the respective electrical cables 16, and these orifices 47 are provided within the front surface 45.

The body 30 includes at least a pair of orifices 47. In the illustrated embodiment, the body 30 has three orifices 47 aligned parallel to the upper surface 40 and the lower surface 42.

Each orifice 47 extends along the orifice shaft 48. For example, each orifice shaft 48 extends parallel to the upper and lower surfaces 40 and 42 of the body 30 and perpendicular to the front surface 45. The entire orifice shaft 48 is included, for example, in the axial plane. The axial plane is, for example, parallel to the first and second surfaces 40, 42.

The body 30 further has, for example, a first cavity 49 on the upper surface 40 and a second cavity on the lower surface 42. In the embodiment shown, only the first cavity 49 is visible.

The first and second cavities 49 are specifically configured to accommodate one or more magnetic elements 32. More precisely, the first cavity 49 is configured to house the first magnetic element 32 and the second cavity is configured to house the second magnetic element 32.

Preferably, the first magnetic element 32 is the same as the second magnetic element 32.

The magnetic element 32 is, for example, a permanent magnet. The magnetic element 32 is oriented to generate a magnetic field along a direction perpendicular to the orifice axis 48 and perpendicular to the upper and lower surfaces 42 in the illustrated embodiment.

Preferably, the first inducing element 34a is the same as the second inducing element 34b. The first and second induction elements 34a, 34b, respectively, are further referred to in the figure by global reference number 34.

The guiding element 34 is a thin plate in the illustrated embodiment. For example, the guiding element 34 is a thin metal plate.

The first guiding element 34a of the magnetic field is fixed on, for example, the upper surface 40, and the second guiding element 34b of the magnetic field is fixed on the lower surface 42. Each guiding element 34 extends in a plane parallel to, for example, the upper surface 40 or the lower surface 42 to which it is fixed. Each guiding element 34 preferably extends beyond the body 30, especially beyond the anterior surface 45. More specifically, each inductive element 34 extends beyond the body 30 so that the electrical terminals 28 sandwich the electrical terminals between the inductive elements when housed in the orifice 47.

The guiding element 34 guides the magnetic field generated by the magnetic element 32 so that the magnetic field is maintained approximately between the first guiding element 34a and the second guiding element 34b.

In other words, the first and second guiding elements 34a, 34b are configured to pass a magnetic field B between them.

The body 30 further includes fins 50 configured to split the arc. The fins 50 project from the front surface 45 and extend along a direction parallel to the orifice shaft 48 and perpendicular to the front surface 45.

The fins 50 include lateral 52 parallel to each other. The side 52 of the fins 50 is oriented towards, for example, the side 52 of the adjacent fins 50.

The fins 50 are spaced apart from each other, for example, by a distance equal to about 5 mm.

More specifically, the body 30 includes a group of at least two fins 50 disposed between the orifices 47 of each orifice pair.

In the embodiment shown in the figure, three fins 50 are fixed on the front surface 45 between the orifices 47 of each orifice pair. In another embodiment, four fins 50 are fixed on the front surface 45 between the orifices 47 of each orifice pair.

The fins 50 are provided, for example, with a conductive U-link (cavalier conducteur) visible in FIG. 5 configured to favor the passage of current in the arc. The conductive U-link is a conductive element comprising two facing side walls capable of at least partially covering each side 52 of the fin 50 and a coupling element connecting the two side walls. is there.

According to the embodiment shown in FIG. 5, each fin 50 is covered with a conductive lining 54.

The lining 54 is formed, for example, by a U-link.

The lining 54 contains, for example, a material that is highly resistant to arcs. This material is, for example, stainless steel.

The lining 54 covers, for example, one end of the fins 50 and at least half of each side 52. In the embodiment of FIG. 5, each lining 54 covers about two-thirds of the side 52.

The fins 50 are configured to split an arc that may occur between the two electrical terminals 28, for example as shown in FIG.

The operation of the power feeding system, particularly the protective device 20, will be described here with reference to FIGS. 3 to 5.

When an arc is formed, it propagates within the feeding system 1. For example, if an arc is formed in the switch 22, the arc propagates in the electrical cable 16 towards the protective device 20 located between the switch 22 and the motor 12.

The magnetic element 32 generates a magnetic field along a direction perpendicular to the upper surface 40 and the lower surface 42.

An example of the first arc generation is shown in FIG. When the current flows in the conductive core wire 24 along the first direction, an arc is generated from the electric terminal 28A toward the electric terminal 28B. The arc exhibits the direction of the current I1.

The arc is deflected by the resultant force F1 by the magnetic field B orthogonal to the current of the arc. The direction of the resultant force F1 is perpendicular to the plane formed by the magnetic field B and the current I1. The resultant force F1 is calculated as follows:
F = BIL
In the ceremony,
B: Magnetic field value,
I: Arc current value,
L: The length of the arc applied to the magnetic field.

The vector of the resultant force F1 is the product of the vector product of the magnetic field and the current vector value multiplied by the length of the arc applied to the magnetic field.

The arc deflected by the resultant force F1 follows the curve C1, as can be seen in FIG. The arc is separated from the main body 30. The deflection of the arc is also called "soufflage".

The curve C1 has a length greater than the shortest distance between the electrical terminals 28A and 28B. The arc voltage increases compared to the undeflected arc. The arc current decreases.

For example, when the current is alternating current, the arc disappears when the current passes through the conductive core wire 24 at zero (lors du passage par ze'ro du courant dans les a ^ mes conductrices 24).

“The current passes at zero” means that the direction of the current in the conductive core wire 24 changes.

An example of the second arc generation is shown in FIG.

When the current flows in the conductive core wire 24 along the second direction opposite to the first direction, the arc is directed from the electric terminal 28A to the electric terminal 28B along the direction of the current I2 of the arc. (See Fig. 4). Upon generation of the arc, the arc is deflected by the magnetic field B, and more precisely by the electrical resultant force F2 along the curve C2. The arc is deflected towards the fins 50.

The resultant force F2 is, for example, parallel to the orifice shaft 48. The resultant force F2 is perpendicular to the plane formed by the magnetic field B and the arc current I2. The calculation of the resultant force F2 corresponds to the calculation of the resultant force F1.

The deflection of the arc towards the fins 50 is also called "aspiration".

When the arc contacts the fin 50, the arc splits into multiple arcs with reduced strength. The fact that the arc splits is shown in FIG. 5 by reduced size flashes.

The arc is then transmitted from one fin 50 to another. During transmission, the arc is damped by a discharge on the fins 50 and lining 54. In the embodiment of FIG. 5, the arc is then transmitted to the electrical terminal 28A.

For example, when the current is alternating current, the arc split between the fins 50 disappears when the current passes through the conductive core wire 24 at zero.

The power supply system 1 and the protective device 20 have a plurality of advantages.

By using a permanent magnet motor, the mass of the motor and the volume of the motor can be reduced. If the motor is a permanent magnet motor, the motor can induce a voltage in the electrical cable 16 as the rail vehicle moves, which can form an arc.

The protection device 20 is an element arranged on the downstream side of the protection device 20, that is, a power supply system 1 arranged between the protection device 20 and the electric motor 12, particularly with respect to the arc in the power supply system 1. Allows you to protect the elements of.

The protective device 20 can further extend the arc between the electrical terminals 28, which reduces the current of the arc. Extension has multiple advantages.

By reducing the arc current, the arc breaking capacity is reduced. The electrical cable 16 is better protected. The protective device 20 can avoid the recurrence of the arc.

In addition, the flash separation further contributes to better protection of the material of the body 30 against the thermal effects of the arc.

Claims (11)

In the protection device (20) for arcing at least two electric cables, each electric cable (16) is a protection device having at least one electric terminal (28, 28A, 28B).
-+ A front surface (45) provided with an orifice (47) intended to accommodate the electrical terminals (28, 28A, 28B) of each of the electrical cables (16), and + the front surface (45). A body (30) having a first surface and a second surface (40, 42) arranged on both sides of the
-At least one magnetic element (32), each magnetic element fixed on the first surface (40) or the second surface, both of which generate one magnetic field (B). Two magnetic elements (32) and
-A first induction element (34a) of the magnetic field (B) fixed to the first surface (40) and a second induction of the magnetic field (B) fixed to the second surface (42). It is an element (34b) and is characterized by having a first guiding element and a second guiding element (34a, 34b) configured to pass the magnetic field (B) between them. Protective device (20). The guiding elements (34a, 34b) are sandwiched between the guiding elements (34a, 34b) when the electrical terminals (28, 28A, 28B) are housed in the orifice (47). The protective device (20) according to claim 1, which extends beyond the main body (30). The body is composed of at least one first magnetic element (32) fixed on the first surface (40) and at least one second magnetic element fixed on the second surface (42). It has a plurality of magnetic elements having (32) and
The protective device (20) according to claim 1 or 2, wherein the first magnetic element and the second magnetic element (32) both generate the magnetic field (B). Each orifice (47) extends along the orifice axis (48) and
The body (30) is a fin (50) configured on the front surface (45) to split the arc, along a direction parallel to each orifice axis (48). The protective device (20) according to any one of claims 1 to 3, which has an extending fin (50). The body (30) has at least one orifice pair (47).
The protection according to any one of claims 1 to 4, wherein the body (40) comprises a group consisting of at least two fins (50) disposed between the orifices (47) of each orifice pair. Equipment (20). The protective device (20) according to claim 4 or 5, wherein each fin (50) is at least partially covered with a lining (54) having stainless steel. The at least one magnetic element (32) is oriented to generate the magnetic field (B) along a direction perpendicular to the first plane and the second plane (40, 42). The protective device (20) according to any one of claims 1 to 6. Each orifice (47) extends along the orifice axis (48) and
The protective device according to any one of claims 1 to 7, wherein the orifice shaft (48) extends parallel to the first surface and the second surface (40, 42). 20). The body (30) has a first cavity (49) on the first surface (40) and a second cavity on the second surface (42).
The first magnetic element (32) is housed in the first cavity (49).
The protective device (20) according to claim 3, wherein the second magnetic element (32) is housed in the second cavity. -At least one electric traction motor (12) and
-An electric connection (14) configured to supply power to the electric motor (12) and having at least one protective device (20) according to any one of claims 1 to 9. (14), and a power supply system for railway vehicles (1). The power supply system (1) according to claim 10, wherein the electric motor (12) is a permanent magnet motor.

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